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Capturing interpretational uncertainty of depositional environments with Artificial Intelligence
Get PDFGeological interpretations are always linked with interpretational and conceptual
uncertainty, which is difficult to elicit and quantify, often creating unquantified risks for
understanding the subsurface. The complexity and variability of geological systems may
lead geologists to analyse the same data and arrive at different conclusions based on their
subjective interpretations, personal expertise, or biases. In order to address the associated
uncertainty, it is valuable to consider multiple plausible interpretations of outcrop data
and acknowledge the degree of ambiguity associated with each interpretation. By
examining a diverse range of outcrop analogues, it becomes possible to derive multiple
potential geological interpretations and identify variations within and across depositional
systems.
This thesis proposes a new AI system that learns valuable geological information from
surface data (outcrop images), transfers this knowledge to the fragmented data of the
subsurface (core data), and finally, links all the extracted information with the geological
literature to produce plausible interpretations of the depositional environment based on a
single outcrop image. To identify patterns and geological features within image data,
three Supervised Learning Computer Vision techniques were employed: Image
Classification, Object Detection, and Instance Segmentation. Natural Language
Processing was utilised to extract geological features from textual information from
heritage geological texts, thus complementing the analysis. Lastly, a custom Neural
Network was deployed to assimilate the gathered information into meaningful sequences,
apply geological constraints to these sequences, and generate multiple plausible
interpretational scenarios, ranked in descending order of probability.
The results of this study demonstrate that combining approaches from different areas of
Artificial Intelligence within cross-disciplinary workflows under the umbrella of a
broader AI system holds significant potential for subsurface characterization, better risk
analysis, and potentially enhancing decision-making under uncertain conditions during
subsurface exploration stages.Heriot-Watt University fundin
Characterisation, analysis and modelling of fabrication error in laser-machined micro-optics
No full textAbstract unavailable. Please refer to PDF. Restricted access until 31.07.2027
Essays on applied spatial econometrics in policy analysis
Get PDFThis thesis examines the role of spatial dependencies under different themes in economic policy setting. It draws on literature from fields such as spatial and network
econometrics, political economy, macroeconomics and economics of climate change
to explore how different patterns of spatial connections are relevant and how they
can be modelled. The contribution is thus provided in four essays. The first essay
studies the design of the Federal Open Market Committee (FOMC) during the periods when Alan Greenspan and Arthur Burns where chairmen. This essay builds on
a theoretical model that assumes that members of committee in the FOMC policy
preferences are influenced by the sectors that they represent. Based on the theoretical model we estimate a network structure of the USA FOMC to understand
exactly how the channels of influence flows within the committee. We apply an
IV-GMM estimation in a spatial econometric framework to estimate a connectivity
matrix and use it for inferences on cross-member interactions within the FOMC.
Our results reveal that there exist significant interaction effects of varying degrees
between FOMC members that influences their policy preferences. This essay also
questions the hypothesis commonly held in the political economic literature about
the Fed chairmen influence by pointing out how this changes when voiced preferences
during deliberations are used instead of actual votes.
The second essay revisits the literature on spatial growth regression by extending
the standard growth model to account for multiple channels of connections between
countries that are purely driven by ’fundamental factors’ of growth. This essay attempts to integrate cultural geography as potential conduit through which countries
interact and how this subsequently effects economic growth. It particularly probes
how common channels of growth between countries such as common currency, bilateral trade relationships, common borders and common historical ties can be tied in
within a spatial growth regression while still also accounting for effects emanating
from institutional or cultural changes. From this, I revisit the Brexit debate by
estimating the spatial connectivity structure (cultural geography) between the UK,
the EU and the Rest of the World (ROW) before the UK joined the EU, when the
UK was part of the EU and make counterfactual arguments to estimate the network
structure in the Post-EU era (Brexit). Our results point out to significant changes
in the connectivity structures before the UK joined the EU and for the Brexit era
which we hypothesise comes from changes in institutional frameworks that are often
not modelled yet they do have identifiable spatial effects across countries.
The third essay extends the existing literature on the open economy DSGE models
by introducing spatial interaction features as a special way of modelling interconnections between countries. We set-up a multi-country DSGE framework and embed
spatial weights to examine potential spatial dependencies. The objective of this
study is three-fold. First, this study aims to identify the best model by employing
a Bayesian model comparison approach. Second, the study estimates the spatial
weights to capture the nature of inter-dependencies that exists between the USA,
Japan and EU. Through the Bayesian model selection, we find that the spatial lag in
the Aggregate Demand is supported by the data based on its high log data density.
The estimation of the positive spatial weights between USA and Japan indicates
positive externalities as a result of technological transfers while the negative spatial
weights between Japan and EU is an indication of negative externalities that could
be as a result of competition in technology.
The fourth essays applies spatial econometric techniques in understanding the economic impacts of climate change on agricultural productivity. We begin by motivating a spatial framework in a standard Levinsohn and Petrins productivity specification. To capture effectively the potential spillover effects from climate change
variables we rewrite the Levinsohn and Petrins productivity specification as a Spatial Durbin Error Model. Doing so allows us to account for spatial spillovers coming
from climate change events in neighbouring units as well as account for unobserved
farm-level characteristics which affects agricultural productivity. This essay also
further attempts to understand how climate change impacts varies across different
municipalities by using high resolution climate data alongside farm-level data. The
discussions and deductions about the implications for climate change in Colombia
are made
Constraining the global climate-active gases flux between atmospheric and water reservoirs
Get PDFGas exchange between air and water bodies is of great importance because of its role in
the biogeochemical cycling of climate, weather and health-related gaseous compounds.
One major challenge of constraining water-atmosphere gas transfer is the direct
measurement of gas transfer velocity (k). Accumulation of the surface-active agents
(surfactants) in the surface microlayer (SML), the interface between atmosphere and
water bodies, can suppress k. There is a large knowledge gap on the properties of
surfactants accumulation in SML and the role of different organic compounds present in
SML on k suppression.
In this research, the organic matter (OM) composition was investigated to monitor the
response of dissolved organic matter (DOM) transport in tropical headwaters which are
largely understudied, yet key global aquatic systems. The hydrological connectivity,
developed during the transition from dry to wet seasons, changes the DOM supply and
transport across the tropical river catchment. The compositional differences between
SML and subsurface water (SSW) which can affect the water-atmosphere gas exchange
were investigated using liquid chromatography-organic carbon detection–organic
nitrogen detection (LC-OCD-OND). This study shows that turbulent flow in the river
homogenises the dissolved organic carbon (DOC) concentration in the water column;
however, DOM is not uniformly distributed and SML and SSW are compositionally
different. It further shows that the changes in the water and DOM source can result in
compositional variability in the water column.
Further study of the impact of the DOM composition in SML on gas exchange, requires
development of a robust, precise, automated gas exchange analyser with high temporal
resolution. Here a novel in-situ method for measuring carbon dioxide (CO2) concentration
in water and air, and k (Insi-K) is introduced. Insi-K was successfully deployed in
freshwater and marine systems demonstrating its capability in a wide range of aquatic
environments. The gas transfer between water and atmosphere is governed by a complex
interplay of kinematic and thermodynamic forcing. Hence, the study of the role of each
process on enhancement or suppression of gas transfer, demands Insi-K as well as a
controlled, sealed and precise gas exchange tank. GETCO2 is next generation of sealed
CO2 gas exchange tanks which uses a method similar to Insi-K for the measurement of CO2 concentration in water and air, and k estimation. The combination of Insi-K and
GETCO2 can assist the profound understanding of the significance of the role of the
controlling processes on water-atmosphere gas exchange
Integration of circular economy strategy as an innovative approach to waste management, within the oil and gas construction projects
Get PDFWaste management within oil and gas construction projects is confronted with significant challenges
due to the industry's complex and large-scale nature, that necessitating a nuanced exploration. The
sector's complexities, characterized by extensive excavation, drilling, and construction undertakings,
contribute to a substantial volume of waste generation. Notably, the presence of hazardous materials
further amplifies the intricacies associated with waste handling and disposal within this industry. The
regulatory landscape adds another layer of complexity, with stringent environmental standards
imposing specific criteria for waste treatment and disposal. Moreover, logistical challenges stemming
from remote project locations and challenging terrains underscore the need for meticulous planning
and resource allocation in waste transportation and disposal. Current linear project delivery methods
deployed in the oil and gas sector predominantly embrace end-of-pipe solutions. These linear
approaches contribute to a heavy reliance on new materials, overlooking opportunities for reusing
construction materials or incorporating sustainable design principles. The lack of integration across
project stages hampers the adoption of circular economy practices, constraining the industry's ability
to shift towards more sustainable and environmentally conscious waste management strategies.
Traditional approaches, including waste sorting, recycling, and landfill disposal, persist despite efforts
to minimize environmental impact.
To provide a contextual background, validate and enhance the research, an assessment of the existing
literature on sustainable construction, waste management strategies was conducted. 15 preliminary
interviews were performed with oil and gas construction project clients, architects, and contractors in
order to identify the construction waste generation challenges related to oil and gas construction
projects. The findings revealed that oil and gas construction projects generate significantly more
waste than other building projects throughout the project lifecycle, identified complex features that
influence waste generation, and identified specific causes of construction waste in oil and gas
construction projects. Similarly, the study discovered various characteristics that shed insight on the
existing practice of the waste management strategy. A deeper investigation was conducted based on
multiple case studies, direct observation, and project documentation analysis to understand the impact
of waste generation due to waste causes, the relationship between complex features in oil and gas
construction projects and waste causes, and best waste minimisation practices to be implemented
throughout the oil and gas construction projects lifecycle to address construction waste causes. During
the data gathering stage, 65 interviews with stakeholders from various case studies were conducted.
The Circular Economy Process Model was then developed based on the findings of the literature
review, the preliminary interview analysis, and the multiple case studies, project documentation,
direct observation, which integrates circular economy principles into the project delivery /
management process. This model is designed to enable the application of the circular economy
concept from the beginning to the end of a construction project and throughout its lifecycle. The
process model was evaluated by 11 industry experts by adopting semi – structured interview to assess its feasibility, functionality, coverage and practicality. The feedback received from the evaluation
demonstrated that the process model is effective in promoting certain aspects of sustainable principles
such as designing for zero waste and encouraging the reuse of project materials and components.
Additionally, the evaluation revealed numerous benefits and potentials of the process model.
In this study, it has been determined that the integration of circular economy principles into the
construction project delivery process can facilitate the reuse of project components and promote a
zero-waste, sustainable environment. The practical outcome of this research is a process model that
can be implemented at all stages of the project management process, enabling the construction
industry to incorporate circular economy principles into their activities. The implementation of this
process model is expected to have a positive impact on the construction industry, as it offers a
solution to reduce the environmental impact of construction activities
Information fusion for situational awareness in urban environments
No full textAbstract unavailable. Please refer to PDF. Restricted access until 28.02.2028.Physical Sciences Research Council (EPSRC) funding
Does a coat matter? The ecotoxicology of modified nanomaterials to Daphnia magna
Get PDFAmong the literature addressing the biological effects of NMs, there is still a lack of
information on NM hazards in relation to their surface modifications. Assessments of the extent
to which such modifications influence NMs’ acute and chronic toxicity, accumulation and
elimination behaviours, as well as specific mechanisms of toxicity are needed to understand
the potential environmental risks these variously modified NMs may pose. Within this thesis,
the effect of surface coating on the toxicity of copper, silver, titanium dioxide and multiwalled
carbon nanotubes was investigated in relation to the freshwater crustacean, Daphnia magna, in
artificial M7 OECD medium. In general, greater toxic potential was observed for Ag NMs and
Cu NMs in contrast to TiO2 NMs and MWCNTs during short term (48 hour) water exposures.
CuO NMs and Ag NMs were found to be toxic during the acute exposures (EC50 values below
100g L-1
) whereas TiO2 NMs (EC50 value determined only for TiO2 (PEG) NMs, 19.94mg L 1
) and MWCNTs did not lead to significant adverse effects in acute studies (EC50 values above
100mg L-1
). Lower toxic potential was observed for pristine NMs compared to surface coated
NMs in the acute toxicity studies. No correlation was observed between average particle size
and surface charge of NMs in M7 medium and acute immobilisation. Mortality, inhibition of
reproduction and growth inhibition were assessed in chronic 21-d exposure tests. 21-d exposure
to MWCNTs and TiO2 NMs inhibited reproduction by 50% at the concentration range from
0.35 to 2.14 mg L-1 and 0.14-0.5 mg L-1
, respectively. Sub-lethal exposure to most tested NMs
inhibited reproduction of D.magna while no such effect was observed for TiO2 (COOH) NMs
where no difference in the number of neonates relative to the control group was recorded.
Carboxy coated NMs showed lower toxic effect on reproduction than pristine and other surface
coated NMs in the chronic exposure test. Exposure to all tested NMs resulted in increased ROS
concentration in relation to control at every time endpoint with significant differences from
control observed for some of them after 2h, 6h and 24h exposure to NMs. Time-dependent
responses were observed for CAT, GST and SOD activities upon exposure of D. magna to
pristine and surface functionalised NMs. The sensitivity in enzymatic responses varied due to
the function of each enzyme. The increasing and decreasing patterns of antioxidant enzyme
activity were varied and depended on exposure time, type of NMs and type of surface coating.
In summary, the toxicity of NMs was influenced by the surface coating regardless the NMs
type. Surface modifications can either enhance or reduce their toxic potential. The results
demonstrate the importance of carrying out a full characterisation of these materials to
understand their potential environmental impact, behaviour in complex environmental matrices
and the mode of toxicity
Manipulation of uncooperative rotating objects in space with a modular self-reconfigurable robot
Get PDFThe following thesis is a feasibility study for the controlled deployment of robotic
scaffolding structures on randomly tumbling objects with low-magnitude gravitational field for use in space applications such as space debris removal, spacecraft
maintenance and asteroids capture and mining. The proposed solution is based on
the novel use of self-reconfigurable modular robots performing deployments on randomly tumbling objects as a task-driven reconfiguration or manipulation through
reconfiguration. The robot design focused on its control strategy which used a
decentralised modular controller with two levels. One high-level behaviour-based
component and one low-level component generating commands via a constrained
optimisation using either a linear or a non-linear model predictive control approach
and constituting a novel control method for rotating objects via angular momentum
exchanges and mass distribution changes. The controller design relied on modelling
the robot modules and the object as a rotating discretised deformable continuum
whose rigid part, the object, was an ellipsoid. All parameters were normalised when
possible and disturbances, sensors and actuator errors were modelled respectively
as biased white noises and coloured noises. The correctness of the overall control
algorithm was ensured. The main objective of the MPC controllers was to control
the deployment of a module from the tip of the spinning axis to the plane containing the object’s centre of mass while coiling around the spinning axis and ensuring
the object’s rotational state tracked a reference state. Simulations showed that the
nonlinear MPC controller should be preferred over a linear one and that, for a mass
ratio of the object’s to the module’s equal to 10000, the nonlinear MPC controller
is best suited to stability maintenance and meets the deployment requirement, suggesting that the proposed solution would be acceptable for medium-size objects such
as asteroids
Gellan gum fluid gels as suspension media for 3D bioprinting of in vitro tissue models
Get PDFEngineering 3-dimensional (3D), vascularised tissues for therapeutic applications, such
as the testing of chemo-therapeutic drugs or organ replacement, remains a major
challenge in human healthcare. Advances in biofabrication, specifically extrusion 3D
bioprinting technologies have driven the development of complex tissue structures by
increasing control over the spatial organisation of cells. Recently, the use of self-healing,
viscoplastic fluids, referred to as suspension media, have been employed in combination
with extrusion 3D printers in order to fabricate more biomimetic structures from soft
water-rich materials. These suspension media have garnered interest as they provide the
required support to prevent structural collapse of a printed material. In this work,
suspension media were developed from sheared gels containing lower than 0.5 % (w/v)
low acyl gellan gum. These gels formed a jammed particle network in which structures
of arbitrary designs or discrete small volumes of cell-laden inks could be printed in 3D
space. Rheological testing was performed on these gels to provide an understanding of
their behaviour at typical bioprinting temperatures, showing these gels demonstrated
viscoplasticity and self-healing abilities at temperatures up to 37 oC. To demonstrate the
versatility of these gels to the tissue engineering field, they were supplemented with
gelatin methacryloyl to enable retention of the suspension medium post-printing via
photocuring. This approach was leveraged to permit fabrication of a large tissue model
within a relatively short fabrication timeframe and to additionally fabricate synthetic
microvascular-like networks by utilising the gellan gum particles to provide support to
printed thermoreversible, sacrificial ink filaments, which were later hollowed post-curing
of the medium
Conservation, reproduction and exploitation of the European lobster (Homarus gammarus L.)
Get PDFEuropean lobster Homarus gammarus fisheries are of significant socio-economic
importance to the coastal communities across the North East Atlantic. Despite this, a
number of key knowledge gaps remain surrounding its fundamental biology, including
aspects highly relevant to sustainable fisheries management at regional and national
levels. Research addressing important knowledge gaps was undertaken during the
development of this thesis that could be used to support sustainable management at
regional, national and international levels.
Geographic patterns of variation in size of maturity (SaM) of male and female lobsters
was investigated across Britain and Ireland, employing the use of standardised maturity
criteria. New data were collected from Orkney whilst working collaboratively with
scientists from Wales, Isle of Man and Ireland to increase geographic coverage. Large
amounts of historical data were used alongside this new data, which enabled large-scale
spatial trends in SaM to be defined for the first time utilising a standardised maturity
criterion. Male morphometric maturity was investigated, demonstrating the use of
morphometrics as a valuable tool for providing evidence to support sustainable
management. Male maturity was shown to follow distinct geographical trends linked to
both sea temperature and fishing exploitation.
Fecundity was investigated through the use of a non-invasive depth gauge technique
previously designed for American lobsters Homarus americanus. This tool also allowed
egg loss to be estimated over a complete brooding cycle, an aspect of reproductive biology
in H. gammarus that is poorly understood and under researched. Finally, geographic
variation in growth was investigated across the entire range of H. gammarus, drawing
upon published and unpublished moult increment data that span populations from the
Adriatic to northern Norway. Geographic variation in lobster moult increments was
identified, with temperature highlighted as a key contributor, however it was not the sole
influencer. Further sex-specific differences in moult increment trends indicate allometric
growth patterns in both sexes, attributed to sexual maturation processes. Regional
variation in double moult occurrence were also investigated, with significant differences
between regions identified, with both pre-moult size and temperature having a significant
effect on this process.
This thesis progress the scientific understanding of H. gammarus by filling key know gaps
by providing standardised methodology and statistical methods to assess maturity. The
establishment of which will benefit stock managers and the long term sustainability
exploitation
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